1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * n_gsm.c GSM 0710 tty multiplexor 4 * Copyright (c) 2009/10 Intel Corporation 5 * 6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * 7 * 8 * TO DO: 9 * Mostly done: ioctls for setting modes/timing 10 * Partly done: hooks so you can pull off frames to non tty devs 11 * Restart DLCI 0 when it closes ? 12 * Improve the tx engine 13 * Resolve tx side locking by adding a queue_head and routing 14 * all control traffic via it 15 * General tidy/document 16 * Review the locking/move to refcounts more (mux now moved to an 17 * alloc/free model ready) 18 * Use newest tty open/close port helpers and install hooks 19 * What to do about power functions ? 20 * Termios setting and negotiation 21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets 22 * 23 */ 24 25 #include <linux/types.h> 26 #include <linux/major.h> 27 #include <linux/errno.h> 28 #include <linux/signal.h> 29 #include <linux/fcntl.h> 30 #include <linux/sched/signal.h> 31 #include <linux/interrupt.h> 32 #include <linux/tty.h> 33 #include <linux/ctype.h> 34 #include <linux/mm.h> 35 #include <linux/string.h> 36 #include <linux/slab.h> 37 #include <linux/poll.h> 38 #include <linux/bitops.h> 39 #include <linux/file.h> 40 #include <linux/uaccess.h> 41 #include <linux/module.h> 42 #include <linux/timer.h> 43 #include <linux/tty_flip.h> 44 #include <linux/tty_driver.h> 45 #include <linux/serial.h> 46 #include <linux/kfifo.h> 47 #include <linux/skbuff.h> 48 #include <net/arp.h> 49 #include <linux/ip.h> 50 #include <linux/netdevice.h> 51 #include <linux/etherdevice.h> 52 #include <linux/gsmmux.h> 53 54 static int debug; 55 module_param(debug, int, 0600); 56 57 /* Defaults: these are from the specification */ 58 59 #define T1 10 /* 100mS */ 60 #define T2 34 /* 333mS */ 61 #define N2 3 /* Retry 3 times */ 62 63 /* Use long timers for testing at low speed with debug on */ 64 #ifdef DEBUG_TIMING 65 #define T1 100 66 #define T2 200 67 #endif 68 69 /* 70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 71 * limits so this is plenty 72 */ 73 #define MAX_MRU 1500 74 #define MAX_MTU 1500 75 #define GSM_NET_TX_TIMEOUT (HZ*10) 76 77 /** 78 * struct gsm_mux_net - network interface 79 * @struct gsm_dlci* dlci 80 * 81 * Created when net interface is initialized. 82 **/ 83 struct gsm_mux_net { 84 struct kref ref; 85 struct gsm_dlci *dlci; 86 }; 87 88 /* 89 * Each block of data we have queued to go out is in the form of 90 * a gsm_msg which holds everything we need in a link layer independent 91 * format 92 */ 93 94 struct gsm_msg { 95 struct list_head list; 96 u8 addr; /* DLCI address + flags */ 97 u8 ctrl; /* Control byte + flags */ 98 unsigned int len; /* Length of data block (can be zero) */ 99 unsigned char *data; /* Points into buffer but not at the start */ 100 unsigned char buffer[]; 101 }; 102 103 enum gsm_dlci_state { 104 DLCI_CLOSED, 105 DLCI_OPENING, /* Sending SABM not seen UA */ 106 DLCI_OPEN, /* SABM/UA complete */ 107 DLCI_CLOSING, /* Sending DISC not seen UA/DM */ 108 }; 109 110 enum gsm_dlci_mode { 111 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */ 112 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */ 113 }; 114 115 /* 116 * Each active data link has a gsm_dlci structure associated which ties 117 * the link layer to an optional tty (if the tty side is open). To avoid 118 * complexity right now these are only ever freed up when the mux is 119 * shut down. 120 * 121 * At the moment we don't free DLCI objects until the mux is torn down 122 * this avoid object life time issues but might be worth review later. 123 */ 124 125 struct gsm_dlci { 126 struct gsm_mux *gsm; 127 int addr; 128 enum gsm_dlci_state state; 129 struct mutex mutex; 130 131 /* Link layer */ 132 enum gsm_dlci_mode mode; 133 spinlock_t lock; /* Protects the internal state */ 134 struct timer_list t1; /* Retransmit timer for SABM and UA */ 135 int retries; 136 /* Uplink tty if active */ 137 struct tty_port port; /* The tty bound to this DLCI if there is one */ 138 struct kfifo fifo; /* Queue fifo for the DLCI */ 139 int adaption; /* Adaption layer in use */ 140 int prev_adaption; 141 u32 modem_rx; /* Our incoming virtual modem lines */ 142 u32 modem_tx; /* Our outgoing modem lines */ 143 bool dead; /* Refuse re-open */ 144 /* Flow control */ 145 bool throttled; /* Private copy of throttle state */ 146 bool constipated; /* Throttle status for outgoing */ 147 /* Packetised I/O */ 148 struct sk_buff *skb; /* Frame being sent */ 149 struct sk_buff_head skb_list; /* Queued frames */ 150 /* Data handling callback */ 151 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len); 152 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len); 153 struct net_device *net; /* network interface, if created */ 154 }; 155 156 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */ 157 158 #define NUM_DLCI 64 159 160 /* 161 * DLCI 0 is used to pass control blocks out of band of the data 162 * flow (and with a higher link priority). One command can be outstanding 163 * at a time and we use this structure to manage them. They are created 164 * and destroyed by the user context, and updated by the receive paths 165 * and timers 166 */ 167 168 struct gsm_control { 169 u8 cmd; /* Command we are issuing */ 170 u8 *data; /* Data for the command in case we retransmit */ 171 int len; /* Length of block for retransmission */ 172 int done; /* Done flag */ 173 int error; /* Error if any */ 174 }; 175 176 enum gsm_mux_state { 177 GSM_SEARCH, 178 GSM_START, 179 GSM_ADDRESS, 180 GSM_CONTROL, 181 GSM_LEN, 182 GSM_DATA, 183 GSM_FCS, 184 GSM_OVERRUN, 185 GSM_LEN0, 186 GSM_LEN1, 187 GSM_SSOF, 188 }; 189 190 /* 191 * Each GSM mux we have is represented by this structure. If we are 192 * operating as an ldisc then we use this structure as our ldisc 193 * state. We need to sort out lifetimes and locking with respect 194 * to the gsm mux array. For now we don't free DLCI objects that 195 * have been instantiated until the mux itself is terminated. 196 * 197 * To consider further: tty open versus mux shutdown. 198 */ 199 200 struct gsm_mux { 201 struct tty_struct *tty; /* The tty our ldisc is bound to */ 202 spinlock_t lock; 203 struct mutex mutex; 204 unsigned int num; 205 struct kref ref; 206 207 /* Events on the GSM channel */ 208 wait_queue_head_t event; 209 210 /* Bits for GSM mode decoding */ 211 212 /* Framing Layer */ 213 unsigned char *buf; 214 enum gsm_mux_state state; 215 unsigned int len; 216 unsigned int address; 217 unsigned int count; 218 bool escape; 219 int encoding; 220 u8 control; 221 u8 fcs; 222 u8 received_fcs; 223 u8 *txframe; /* TX framing buffer */ 224 225 /* Methods for the receiver side */ 226 void (*receive)(struct gsm_mux *gsm, u8 ch); 227 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 228 /* And transmit side */ 229 int (*output)(struct gsm_mux *mux, u8 *data, int len); 230 231 /* Link Layer */ 232 unsigned int mru; 233 unsigned int mtu; 234 int initiator; /* Did we initiate connection */ 235 bool dead; /* Has the mux been shut down */ 236 struct gsm_dlci *dlci[NUM_DLCI]; 237 bool constipated; /* Asked by remote to shut up */ 238 239 spinlock_t tx_lock; 240 unsigned int tx_bytes; /* TX data outstanding */ 241 #define TX_THRESH_HI 8192 242 #define TX_THRESH_LO 2048 243 struct list_head tx_list; /* Pending data packets */ 244 245 /* Control messages */ 246 struct timer_list t2_timer; /* Retransmit timer for commands */ 247 int cretries; /* Command retry counter */ 248 struct gsm_control *pending_cmd;/* Our current pending command */ 249 spinlock_t control_lock; /* Protects the pending command */ 250 251 /* Configuration */ 252 int adaption; /* 1 or 2 supported */ 253 u8 ftype; /* UI or UIH */ 254 int t1, t2; /* Timers in 1/100th of a sec */ 255 int n2; /* Retry count */ 256 257 /* Statistics (not currently exposed) */ 258 unsigned long bad_fcs; 259 unsigned long malformed; 260 unsigned long io_error; 261 unsigned long bad_size; 262 unsigned long unsupported; 263 }; 264 265 266 /* 267 * Mux objects - needed so that we can translate a tty index into the 268 * relevant mux and DLCI. 269 */ 270 271 #define MAX_MUX 4 /* 256 minors */ 272 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 273 static spinlock_t gsm_mux_lock; 274 275 static struct tty_driver *gsm_tty_driver; 276 277 /* 278 * This section of the driver logic implements the GSM encodings 279 * both the basic and the 'advanced'. Reliable transport is not 280 * supported. 281 */ 282 283 #define CR 0x02 284 #define EA 0x01 285 #define PF 0x10 286 287 /* I is special: the rest are ..*/ 288 #define RR 0x01 289 #define UI 0x03 290 #define RNR 0x05 291 #define REJ 0x09 292 #define DM 0x0F 293 #define SABM 0x2F 294 #define DISC 0x43 295 #define UA 0x63 296 #define UIH 0xEF 297 298 /* Channel commands */ 299 #define CMD_NSC 0x09 300 #define CMD_TEST 0x11 301 #define CMD_PSC 0x21 302 #define CMD_RLS 0x29 303 #define CMD_FCOFF 0x31 304 #define CMD_PN 0x41 305 #define CMD_RPN 0x49 306 #define CMD_FCON 0x51 307 #define CMD_CLD 0x61 308 #define CMD_SNC 0x69 309 #define CMD_MSC 0x71 310 311 /* Virtual modem bits */ 312 #define MDM_FC 0x01 313 #define MDM_RTC 0x02 314 #define MDM_RTR 0x04 315 #define MDM_IC 0x20 316 #define MDM_DV 0x40 317 318 #define GSM0_SOF 0xF9 319 #define GSM1_SOF 0x7E 320 #define GSM1_ESCAPE 0x7D 321 #define GSM1_ESCAPE_BITS 0x20 322 #define XON 0x11 323 #define XOFF 0x13 324 325 static const struct tty_port_operations gsm_port_ops; 326 327 /* 328 * CRC table for GSM 0710 329 */ 330 331 static const u8 gsm_fcs8[256] = { 332 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 333 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 334 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 335 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 336 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 337 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 338 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 339 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 340 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 341 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 342 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 343 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 344 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 345 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 346 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 347 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 348 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 349 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 350 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 351 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 352 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 353 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 354 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 355 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 356 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 357 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 358 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 359 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 360 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 361 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 362 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 363 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 364 }; 365 366 #define INIT_FCS 0xFF 367 #define GOOD_FCS 0xCF 368 369 /** 370 * gsm_fcs_add - update FCS 371 * @fcs: Current FCS 372 * @c: Next data 373 * 374 * Update the FCS to include c. Uses the algorithm in the specification 375 * notes. 376 */ 377 378 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 379 { 380 return gsm_fcs8[fcs ^ c]; 381 } 382 383 /** 384 * gsm_fcs_add_block - update FCS for a block 385 * @fcs: Current FCS 386 * @c: buffer of data 387 * @len: length of buffer 388 * 389 * Update the FCS to include c. Uses the algorithm in the specification 390 * notes. 391 */ 392 393 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 394 { 395 while (len--) 396 fcs = gsm_fcs8[fcs ^ *c++]; 397 return fcs; 398 } 399 400 /** 401 * gsm_read_ea - read a byte into an EA 402 * @val: variable holding value 403 * c: byte going into the EA 404 * 405 * Processes one byte of an EA. Updates the passed variable 406 * and returns 1 if the EA is now completely read 407 */ 408 409 static int gsm_read_ea(unsigned int *val, u8 c) 410 { 411 /* Add the next 7 bits into the value */ 412 *val <<= 7; 413 *val |= c >> 1; 414 /* Was this the last byte of the EA 1 = yes*/ 415 return c & EA; 416 } 417 418 /** 419 * gsm_encode_modem - encode modem data bits 420 * @dlci: DLCI to encode from 421 * 422 * Returns the correct GSM encoded modem status bits (6 bit field) for 423 * the current status of the DLCI and attached tty object 424 */ 425 426 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 427 { 428 u8 modembits = 0; 429 /* FC is true flow control not modem bits */ 430 if (dlci->throttled) 431 modembits |= MDM_FC; 432 if (dlci->modem_tx & TIOCM_DTR) 433 modembits |= MDM_RTC; 434 if (dlci->modem_tx & TIOCM_RTS) 435 modembits |= MDM_RTR; 436 if (dlci->modem_tx & TIOCM_RI) 437 modembits |= MDM_IC; 438 if (dlci->modem_tx & TIOCM_CD) 439 modembits |= MDM_DV; 440 return modembits; 441 } 442 443 /** 444 * gsm_print_packet - display a frame for debug 445 * @hdr: header to print before decode 446 * @addr: address EA from the frame 447 * @cr: C/R bit from the frame 448 * @control: control including PF bit 449 * @data: following data bytes 450 * @dlen: length of data 451 * 452 * Displays a packet in human readable format for debugging purposes. The 453 * style is based on amateur radio LAP-B dump display. 454 */ 455 456 static void gsm_print_packet(const char *hdr, int addr, int cr, 457 u8 control, const u8 *data, int dlen) 458 { 459 if (!(debug & 1)) 460 return; 461 462 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 463 464 switch (control & ~PF) { 465 case SABM: 466 pr_cont("SABM"); 467 break; 468 case UA: 469 pr_cont("UA"); 470 break; 471 case DISC: 472 pr_cont("DISC"); 473 break; 474 case DM: 475 pr_cont("DM"); 476 break; 477 case UI: 478 pr_cont("UI"); 479 break; 480 case UIH: 481 pr_cont("UIH"); 482 break; 483 default: 484 if (!(control & 0x01)) { 485 pr_cont("I N(S)%d N(R)%d", 486 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 487 } else switch (control & 0x0F) { 488 case RR: 489 pr_cont("RR(%d)", (control & 0xE0) >> 5); 490 break; 491 case RNR: 492 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 493 break; 494 case REJ: 495 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 496 break; 497 default: 498 pr_cont("[%02X]", control); 499 } 500 } 501 502 if (control & PF) 503 pr_cont("(P)"); 504 else 505 pr_cont("(F)"); 506 507 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen); 508 } 509 510 511 /* 512 * Link level transmission side 513 */ 514 515 /** 516 * gsm_stuff_packet - bytestuff a packet 517 * @ibuf: input 518 * @obuf: output 519 * @len: length of input 520 * 521 * Expand a buffer by bytestuffing it. The worst case size change 522 * is doubling and the caller is responsible for handing out 523 * suitable sized buffers. 524 */ 525 526 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 527 { 528 int olen = 0; 529 while (len--) { 530 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 531 || *input == XON || *input == XOFF) { 532 *output++ = GSM1_ESCAPE; 533 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 534 olen++; 535 } else 536 *output++ = *input++; 537 olen++; 538 } 539 return olen; 540 } 541 542 /** 543 * gsm_send - send a control frame 544 * @gsm: our GSM mux 545 * @addr: address for control frame 546 * @cr: command/response bit 547 * @control: control byte including PF bit 548 * 549 * Format up and transmit a control frame. These do not go via the 550 * queueing logic as they should be transmitted ahead of data when 551 * they are needed. 552 * 553 * FIXME: Lock versus data TX path 554 */ 555 556 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 557 { 558 int len; 559 u8 cbuf[10]; 560 u8 ibuf[3]; 561 562 switch (gsm->encoding) { 563 case 0: 564 cbuf[0] = GSM0_SOF; 565 cbuf[1] = (addr << 2) | (cr << 1) | EA; 566 cbuf[2] = control; 567 cbuf[3] = EA; /* Length of data = 0 */ 568 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); 569 cbuf[5] = GSM0_SOF; 570 len = 6; 571 break; 572 case 1: 573 case 2: 574 /* Control frame + packing (but not frame stuffing) in mode 1 */ 575 ibuf[0] = (addr << 2) | (cr << 1) | EA; 576 ibuf[1] = control; 577 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); 578 /* Stuffing may double the size worst case */ 579 len = gsm_stuff_frame(ibuf, cbuf + 1, 3); 580 /* Now add the SOF markers */ 581 cbuf[0] = GSM1_SOF; 582 cbuf[len + 1] = GSM1_SOF; 583 /* FIXME: we can omit the lead one in many cases */ 584 len += 2; 585 break; 586 default: 587 WARN_ON(1); 588 return; 589 } 590 gsm->output(gsm, cbuf, len); 591 gsm_print_packet("-->", addr, cr, control, NULL, 0); 592 } 593 594 /** 595 * gsm_response - send a control response 596 * @gsm: our GSM mux 597 * @addr: address for control frame 598 * @control: control byte including PF bit 599 * 600 * Format up and transmit a link level response frame. 601 */ 602 603 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 604 { 605 gsm_send(gsm, addr, 0, control); 606 } 607 608 /** 609 * gsm_command - send a control command 610 * @gsm: our GSM mux 611 * @addr: address for control frame 612 * @control: control byte including PF bit 613 * 614 * Format up and transmit a link level command frame. 615 */ 616 617 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 618 { 619 gsm_send(gsm, addr, 1, control); 620 } 621 622 /* Data transmission */ 623 624 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 625 626 /** 627 * gsm_data_alloc - allocate data frame 628 * @gsm: GSM mux 629 * @addr: DLCI address 630 * @len: length excluding header and FCS 631 * @ctrl: control byte 632 * 633 * Allocate a new data buffer for sending frames with data. Space is left 634 * at the front for header bytes but that is treated as an implementation 635 * detail and not for the high level code to use 636 */ 637 638 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 639 u8 ctrl) 640 { 641 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 642 GFP_ATOMIC); 643 if (m == NULL) 644 return NULL; 645 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 646 m->len = len; 647 m->addr = addr; 648 m->ctrl = ctrl; 649 INIT_LIST_HEAD(&m->list); 650 return m; 651 } 652 653 /** 654 * gsm_data_kick - poke the queue 655 * @gsm: GSM Mux 656 * 657 * The tty device has called us to indicate that room has appeared in 658 * the transmit queue. Ram more data into the pipe if we have any 659 * If we have been flow-stopped by a CMD_FCOFF, then we can only 660 * send messages on DLCI0 until CMD_FCON 661 * 662 * FIXME: lock against link layer control transmissions 663 */ 664 665 static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci) 666 { 667 struct gsm_msg *msg, *nmsg; 668 int len; 669 670 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { 671 if (gsm->constipated && msg->addr) 672 continue; 673 if (gsm->encoding != 0) { 674 gsm->txframe[0] = GSM1_SOF; 675 len = gsm_stuff_frame(msg->data, 676 gsm->txframe + 1, msg->len); 677 gsm->txframe[len + 1] = GSM1_SOF; 678 len += 2; 679 } else { 680 gsm->txframe[0] = GSM0_SOF; 681 memcpy(gsm->txframe + 1 , msg->data, msg->len); 682 gsm->txframe[msg->len + 1] = GSM0_SOF; 683 len = msg->len + 2; 684 } 685 686 if (debug & 4) 687 print_hex_dump_bytes("gsm_data_kick: ", 688 DUMP_PREFIX_OFFSET, 689 gsm->txframe, len); 690 if (gsm->output(gsm, gsm->txframe, len) < 0) 691 break; 692 /* FIXME: Can eliminate one SOF in many more cases */ 693 gsm->tx_bytes -= msg->len; 694 695 list_del(&msg->list); 696 kfree(msg); 697 698 if (dlci) { 699 tty_port_tty_wakeup(&dlci->port); 700 } else { 701 int i = 0; 702 703 for (i = 0; i < NUM_DLCI; i++) 704 if (gsm->dlci[i]) 705 tty_port_tty_wakeup(&gsm->dlci[i]->port); 706 } 707 } 708 } 709 710 /** 711 * __gsm_data_queue - queue a UI or UIH frame 712 * @dlci: DLCI sending the data 713 * @msg: message queued 714 * 715 * Add data to the transmit queue and try and get stuff moving 716 * out of the mux tty if not already doing so. The Caller must hold 717 * the gsm tx lock. 718 */ 719 720 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 721 { 722 struct gsm_mux *gsm = dlci->gsm; 723 u8 *dp = msg->data; 724 u8 *fcs = dp + msg->len; 725 726 /* Fill in the header */ 727 if (gsm->encoding == 0) { 728 if (msg->len < 128) 729 *--dp = (msg->len << 1) | EA; 730 else { 731 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 732 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 733 } 734 } 735 736 *--dp = msg->ctrl; 737 if (gsm->initiator) 738 *--dp = (msg->addr << 2) | 2 | EA; 739 else 740 *--dp = (msg->addr << 2) | EA; 741 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 742 /* Ugly protocol layering violation */ 743 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 744 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 745 *fcs = 0xFF - *fcs; 746 747 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 748 msg->data, msg->len); 749 750 /* Move the header back and adjust the length, also allow for the FCS 751 now tacked on the end */ 752 msg->len += (msg->data - dp) + 1; 753 msg->data = dp; 754 755 /* Add to the actual output queue */ 756 list_add_tail(&msg->list, &gsm->tx_list); 757 gsm->tx_bytes += msg->len; 758 gsm_data_kick(gsm, dlci); 759 } 760 761 /** 762 * gsm_data_queue - queue a UI or UIH frame 763 * @dlci: DLCI sending the data 764 * @msg: message queued 765 * 766 * Add data to the transmit queue and try and get stuff moving 767 * out of the mux tty if not already doing so. Take the 768 * the gsm tx lock and dlci lock. 769 */ 770 771 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 772 { 773 unsigned long flags; 774 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 775 __gsm_data_queue(dlci, msg); 776 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 777 } 778 779 /** 780 * gsm_dlci_data_output - try and push data out of a DLCI 781 * @gsm: mux 782 * @dlci: the DLCI to pull data from 783 * 784 * Pull data from a DLCI and send it into the transmit queue if there 785 * is data. Keep to the MRU of the mux. This path handles the usual tty 786 * interface which is a byte stream with optional modem data. 787 * 788 * Caller must hold the tx_lock of the mux. 789 */ 790 791 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 792 { 793 struct gsm_msg *msg; 794 u8 *dp; 795 int len, total_size, size; 796 int h = dlci->adaption - 1; 797 798 total_size = 0; 799 while (1) { 800 len = kfifo_len(&dlci->fifo); 801 if (len == 0) 802 return total_size; 803 804 /* MTU/MRU count only the data bits */ 805 if (len > gsm->mtu) 806 len = gsm->mtu; 807 808 size = len + h; 809 810 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 811 /* FIXME: need a timer or something to kick this so it can't 812 get stuck with no work outstanding and no buffer free */ 813 if (msg == NULL) 814 return -ENOMEM; 815 dp = msg->data; 816 switch (dlci->adaption) { 817 case 1: /* Unstructured */ 818 break; 819 case 2: /* Unstructed with modem bits. 820 Always one byte as we never send inline break data */ 821 *dp++ = gsm_encode_modem(dlci); 822 break; 823 } 824 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len); 825 __gsm_data_queue(dlci, msg); 826 total_size += size; 827 } 828 /* Bytes of data we used up */ 829 return total_size; 830 } 831 832 /** 833 * gsm_dlci_data_output_framed - try and push data out of a DLCI 834 * @gsm: mux 835 * @dlci: the DLCI to pull data from 836 * 837 * Pull data from a DLCI and send it into the transmit queue if there 838 * is data. Keep to the MRU of the mux. This path handles framed data 839 * queued as skbuffs to the DLCI. 840 * 841 * Caller must hold the tx_lock of the mux. 842 */ 843 844 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 845 struct gsm_dlci *dlci) 846 { 847 struct gsm_msg *msg; 848 u8 *dp; 849 int len, size; 850 int last = 0, first = 0; 851 int overhead = 0; 852 853 /* One byte per frame is used for B/F flags */ 854 if (dlci->adaption == 4) 855 overhead = 1; 856 857 /* dlci->skb is locked by tx_lock */ 858 if (dlci->skb == NULL) { 859 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 860 if (dlci->skb == NULL) 861 return 0; 862 first = 1; 863 } 864 len = dlci->skb->len + overhead; 865 866 /* MTU/MRU count only the data bits */ 867 if (len > gsm->mtu) { 868 if (dlci->adaption == 3) { 869 /* Over long frame, bin it */ 870 dev_kfree_skb_any(dlci->skb); 871 dlci->skb = NULL; 872 return 0; 873 } 874 len = gsm->mtu; 875 } else 876 last = 1; 877 878 size = len + overhead; 879 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 880 881 /* FIXME: need a timer or something to kick this so it can't 882 get stuck with no work outstanding and no buffer free */ 883 if (msg == NULL) { 884 skb_queue_tail(&dlci->skb_list, dlci->skb); 885 dlci->skb = NULL; 886 return -ENOMEM; 887 } 888 dp = msg->data; 889 890 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 891 /* Flag byte to carry the start/end info */ 892 *dp++ = last << 7 | first << 6 | 1; /* EA */ 893 len--; 894 } 895 memcpy(dp, dlci->skb->data, len); 896 skb_pull(dlci->skb, len); 897 __gsm_data_queue(dlci, msg); 898 if (last) { 899 dev_kfree_skb_any(dlci->skb); 900 dlci->skb = NULL; 901 } 902 return size; 903 } 904 905 /** 906 * gsm_dlci_data_sweep - look for data to send 907 * @gsm: the GSM mux 908 * 909 * Sweep the GSM mux channels in priority order looking for ones with 910 * data to send. We could do with optimising this scan a bit. We aim 911 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 912 * TX_THRESH_LO we get called again 913 * 914 * FIXME: We should round robin between groups and in theory you can 915 * renegotiate DLCI priorities with optional stuff. Needs optimising. 916 */ 917 918 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 919 { 920 int len; 921 /* Priority ordering: We should do priority with RR of the groups */ 922 int i = 1; 923 924 while (i < NUM_DLCI) { 925 struct gsm_dlci *dlci; 926 927 if (gsm->tx_bytes > TX_THRESH_HI) 928 break; 929 dlci = gsm->dlci[i]; 930 if (dlci == NULL || dlci->constipated) { 931 i++; 932 continue; 933 } 934 if (dlci->adaption < 3 && !dlci->net) 935 len = gsm_dlci_data_output(gsm, dlci); 936 else 937 len = gsm_dlci_data_output_framed(gsm, dlci); 938 if (len < 0) 939 break; 940 /* DLCI empty - try the next */ 941 if (len == 0) 942 i++; 943 } 944 } 945 946 /** 947 * gsm_dlci_data_kick - transmit if possible 948 * @dlci: DLCI to kick 949 * 950 * Transmit data from this DLCI if the queue is empty. We can't rely on 951 * a tty wakeup except when we filled the pipe so we need to fire off 952 * new data ourselves in other cases. 953 */ 954 955 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 956 { 957 unsigned long flags; 958 int sweep; 959 960 if (dlci->constipated) 961 return; 962 963 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 964 /* If we have nothing running then we need to fire up */ 965 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 966 if (dlci->gsm->tx_bytes == 0) { 967 if (dlci->net) 968 gsm_dlci_data_output_framed(dlci->gsm, dlci); 969 else 970 gsm_dlci_data_output(dlci->gsm, dlci); 971 } 972 if (sweep) 973 gsm_dlci_data_sweep(dlci->gsm); 974 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 975 } 976 977 /* 978 * Control message processing 979 */ 980 981 982 /** 983 * gsm_control_reply - send a response frame to a control 984 * @gsm: gsm channel 985 * @cmd: the command to use 986 * @data: data to follow encoded info 987 * @dlen: length of data 988 * 989 * Encode up and queue a UI/UIH frame containing our response. 990 */ 991 992 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data, 993 int dlen) 994 { 995 struct gsm_msg *msg; 996 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 997 if (msg == NULL) 998 return; 999 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1000 msg->data[1] = (dlen << 1) | EA; 1001 memcpy(msg->data + 2, data, dlen); 1002 gsm_data_queue(gsm->dlci[0], msg); 1003 } 1004 1005 /** 1006 * gsm_process_modem - process received modem status 1007 * @tty: virtual tty bound to the DLCI 1008 * @dlci: DLCI to affect 1009 * @modem: modem bits (full EA) 1010 * 1011 * Used when a modem control message or line state inline in adaption 1012 * layer 2 is processed. Sort out the local modem state and throttles 1013 */ 1014 1015 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1016 u32 modem, int clen) 1017 { 1018 int mlines = 0; 1019 u8 brk = 0; 1020 int fc; 1021 1022 /* The modem status command can either contain one octet (v.24 signals) 1023 or two octets (v.24 signals + break signals). The length field will 1024 either be 2 or 3 respectively. This is specified in section 1025 5.4.6.3.7 of the 27.010 mux spec. */ 1026 1027 if (clen == 2) 1028 modem = modem & 0x7f; 1029 else { 1030 brk = modem & 0x7f; 1031 modem = (modem >> 7) & 0x7f; 1032 } 1033 1034 /* Flow control/ready to communicate */ 1035 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1036 if (fc && !dlci->constipated) { 1037 /* Need to throttle our output on this device */ 1038 dlci->constipated = true; 1039 } else if (!fc && dlci->constipated) { 1040 dlci->constipated = false; 1041 gsm_dlci_data_kick(dlci); 1042 } 1043 1044 /* Map modem bits */ 1045 if (modem & MDM_RTC) 1046 mlines |= TIOCM_DSR | TIOCM_DTR; 1047 if (modem & MDM_RTR) 1048 mlines |= TIOCM_RTS | TIOCM_CTS; 1049 if (modem & MDM_IC) 1050 mlines |= TIOCM_RI; 1051 if (modem & MDM_DV) 1052 mlines |= TIOCM_CD; 1053 1054 /* Carrier drop -> hangup */ 1055 if (tty) { 1056 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1057 if (!C_CLOCAL(tty)) 1058 tty_hangup(tty); 1059 } 1060 if (brk & 0x01) 1061 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1062 dlci->modem_rx = mlines; 1063 } 1064 1065 /** 1066 * gsm_control_modem - modem status received 1067 * @gsm: GSM channel 1068 * @data: data following command 1069 * @clen: command length 1070 * 1071 * We have received a modem status control message. This is used by 1072 * the GSM mux protocol to pass virtual modem line status and optionally 1073 * to indicate break signals. Unpack it, convert to Linux representation 1074 * and if need be stuff a break message down the tty. 1075 */ 1076 1077 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) 1078 { 1079 unsigned int addr = 0; 1080 unsigned int modem = 0; 1081 unsigned int brk = 0; 1082 struct gsm_dlci *dlci; 1083 int len = clen; 1084 const u8 *dp = data; 1085 struct tty_struct *tty; 1086 1087 while (gsm_read_ea(&addr, *dp++) == 0) { 1088 len--; 1089 if (len == 0) 1090 return; 1091 } 1092 /* Must be at least one byte following the EA */ 1093 len--; 1094 if (len <= 0) 1095 return; 1096 1097 addr >>= 1; 1098 /* Closed port, or invalid ? */ 1099 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1100 return; 1101 dlci = gsm->dlci[addr]; 1102 1103 while (gsm_read_ea(&modem, *dp++) == 0) { 1104 len--; 1105 if (len == 0) 1106 return; 1107 } 1108 len--; 1109 if (len > 0) { 1110 while (gsm_read_ea(&brk, *dp++) == 0) { 1111 len--; 1112 if (len == 0) 1113 return; 1114 } 1115 modem <<= 7; 1116 modem |= (brk & 0x7f); 1117 } 1118 tty = tty_port_tty_get(&dlci->port); 1119 gsm_process_modem(tty, dlci, modem, clen); 1120 if (tty) { 1121 tty_wakeup(tty); 1122 tty_kref_put(tty); 1123 } 1124 gsm_control_reply(gsm, CMD_MSC, data, clen); 1125 } 1126 1127 /** 1128 * gsm_control_rls - remote line status 1129 * @gsm: GSM channel 1130 * @data: data bytes 1131 * @clen: data length 1132 * 1133 * The modem sends us a two byte message on the control channel whenever 1134 * it wishes to send us an error state from the virtual link. Stuff 1135 * this into the uplink tty if present 1136 */ 1137 1138 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) 1139 { 1140 struct tty_port *port; 1141 unsigned int addr = 0; 1142 u8 bits; 1143 int len = clen; 1144 const u8 *dp = data; 1145 1146 while (gsm_read_ea(&addr, *dp++) == 0) { 1147 len--; 1148 if (len == 0) 1149 return; 1150 } 1151 /* Must be at least one byte following ea */ 1152 len--; 1153 if (len <= 0) 1154 return; 1155 addr >>= 1; 1156 /* Closed port, or invalid ? */ 1157 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1158 return; 1159 /* No error ? */ 1160 bits = *dp; 1161 if ((bits & 1) == 0) 1162 return; 1163 1164 port = &gsm->dlci[addr]->port; 1165 1166 if (bits & 2) 1167 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1168 if (bits & 4) 1169 tty_insert_flip_char(port, 0, TTY_PARITY); 1170 if (bits & 8) 1171 tty_insert_flip_char(port, 0, TTY_FRAME); 1172 1173 tty_flip_buffer_push(port); 1174 1175 gsm_control_reply(gsm, CMD_RLS, data, clen); 1176 } 1177 1178 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1179 1180 /** 1181 * gsm_control_message - DLCI 0 control processing 1182 * @gsm: our GSM mux 1183 * @command: the command EA 1184 * @data: data beyond the command/length EAs 1185 * @clen: length 1186 * 1187 * Input processor for control messages from the other end of the link. 1188 * Processes the incoming request and queues a response frame or an 1189 * NSC response if not supported 1190 */ 1191 1192 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1193 const u8 *data, int clen) 1194 { 1195 u8 buf[1]; 1196 unsigned long flags; 1197 1198 switch (command) { 1199 case CMD_CLD: { 1200 struct gsm_dlci *dlci = gsm->dlci[0]; 1201 /* Modem wishes to close down */ 1202 if (dlci) { 1203 dlci->dead = true; 1204 gsm->dead = true; 1205 gsm_dlci_begin_close(dlci); 1206 } 1207 } 1208 break; 1209 case CMD_TEST: 1210 /* Modem wishes to test, reply with the data */ 1211 gsm_control_reply(gsm, CMD_TEST, data, clen); 1212 break; 1213 case CMD_FCON: 1214 /* Modem can accept data again */ 1215 gsm->constipated = false; 1216 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1217 /* Kick the link in case it is idling */ 1218 spin_lock_irqsave(&gsm->tx_lock, flags); 1219 gsm_data_kick(gsm, NULL); 1220 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1221 break; 1222 case CMD_FCOFF: 1223 /* Modem wants us to STFU */ 1224 gsm->constipated = true; 1225 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1226 break; 1227 case CMD_MSC: 1228 /* Out of band modem line change indicator for a DLCI */ 1229 gsm_control_modem(gsm, data, clen); 1230 break; 1231 case CMD_RLS: 1232 /* Out of band error reception for a DLCI */ 1233 gsm_control_rls(gsm, data, clen); 1234 break; 1235 case CMD_PSC: 1236 /* Modem wishes to enter power saving state */ 1237 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1238 break; 1239 /* Optional unsupported commands */ 1240 case CMD_PN: /* Parameter negotiation */ 1241 case CMD_RPN: /* Remote port negotiation */ 1242 case CMD_SNC: /* Service negotiation command */ 1243 default: 1244 /* Reply to bad commands with an NSC */ 1245 buf[0] = command; 1246 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1247 break; 1248 } 1249 } 1250 1251 /** 1252 * gsm_control_response - process a response to our control 1253 * @gsm: our GSM mux 1254 * @command: the command (response) EA 1255 * @data: data beyond the command/length EA 1256 * @clen: length 1257 * 1258 * Process a response to an outstanding command. We only allow a single 1259 * control message in flight so this is fairly easy. All the clean up 1260 * is done by the caller, we just update the fields, flag it as done 1261 * and return 1262 */ 1263 1264 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1265 const u8 *data, int clen) 1266 { 1267 struct gsm_control *ctrl; 1268 unsigned long flags; 1269 1270 spin_lock_irqsave(&gsm->control_lock, flags); 1271 1272 ctrl = gsm->pending_cmd; 1273 /* Does the reply match our command */ 1274 command |= 1; 1275 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1276 /* Our command was replied to, kill the retry timer */ 1277 del_timer(&gsm->t2_timer); 1278 gsm->pending_cmd = NULL; 1279 /* Rejected by the other end */ 1280 if (command == CMD_NSC) 1281 ctrl->error = -EOPNOTSUPP; 1282 ctrl->done = 1; 1283 wake_up(&gsm->event); 1284 } 1285 spin_unlock_irqrestore(&gsm->control_lock, flags); 1286 } 1287 1288 /** 1289 * gsm_control_transmit - send control packet 1290 * @gsm: gsm mux 1291 * @ctrl: frame to send 1292 * 1293 * Send out a pending control command (called under control lock) 1294 */ 1295 1296 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1297 { 1298 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1299 if (msg == NULL) 1300 return; 1301 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1302 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1303 gsm_data_queue(gsm->dlci[0], msg); 1304 } 1305 1306 /** 1307 * gsm_control_retransmit - retransmit a control frame 1308 * @data: pointer to our gsm object 1309 * 1310 * Called off the T2 timer expiry in order to retransmit control frames 1311 * that have been lost in the system somewhere. The control_lock protects 1312 * us from colliding with another sender or a receive completion event. 1313 * In that situation the timer may still occur in a small window but 1314 * gsm->pending_cmd will be NULL and we just let the timer expire. 1315 */ 1316 1317 static void gsm_control_retransmit(struct timer_list *t) 1318 { 1319 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer); 1320 struct gsm_control *ctrl; 1321 unsigned long flags; 1322 spin_lock_irqsave(&gsm->control_lock, flags); 1323 ctrl = gsm->pending_cmd; 1324 if (ctrl) { 1325 gsm->cretries--; 1326 if (gsm->cretries == 0) { 1327 gsm->pending_cmd = NULL; 1328 ctrl->error = -ETIMEDOUT; 1329 ctrl->done = 1; 1330 spin_unlock_irqrestore(&gsm->control_lock, flags); 1331 wake_up(&gsm->event); 1332 return; 1333 } 1334 gsm_control_transmit(gsm, ctrl); 1335 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1336 } 1337 spin_unlock_irqrestore(&gsm->control_lock, flags); 1338 } 1339 1340 /** 1341 * gsm_control_send - send a control frame on DLCI 0 1342 * @gsm: the GSM channel 1343 * @command: command to send including CR bit 1344 * @data: bytes of data (must be kmalloced) 1345 * @len: length of the block to send 1346 * 1347 * Queue and dispatch a control command. Only one command can be 1348 * active at a time. In theory more can be outstanding but the matching 1349 * gets really complicated so for now stick to one outstanding. 1350 */ 1351 1352 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1353 unsigned int command, u8 *data, int clen) 1354 { 1355 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1356 GFP_KERNEL); 1357 unsigned long flags; 1358 if (ctrl == NULL) 1359 return NULL; 1360 retry: 1361 wait_event(gsm->event, gsm->pending_cmd == NULL); 1362 spin_lock_irqsave(&gsm->control_lock, flags); 1363 if (gsm->pending_cmd != NULL) { 1364 spin_unlock_irqrestore(&gsm->control_lock, flags); 1365 goto retry; 1366 } 1367 ctrl->cmd = command; 1368 ctrl->data = data; 1369 ctrl->len = clen; 1370 gsm->pending_cmd = ctrl; 1371 1372 /* If DLCI0 is in ADM mode skip retries, it won't respond */ 1373 if (gsm->dlci[0]->mode == DLCI_MODE_ADM) 1374 gsm->cretries = 1; 1375 else 1376 gsm->cretries = gsm->n2; 1377 1378 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1379 gsm_control_transmit(gsm, ctrl); 1380 spin_unlock_irqrestore(&gsm->control_lock, flags); 1381 return ctrl; 1382 } 1383 1384 /** 1385 * gsm_control_wait - wait for a control to finish 1386 * @gsm: GSM mux 1387 * @control: control we are waiting on 1388 * 1389 * Waits for the control to complete or time out. Frees any used 1390 * resources and returns 0 for success, or an error if the remote 1391 * rejected or ignored the request. 1392 */ 1393 1394 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1395 { 1396 int err; 1397 wait_event(gsm->event, control->done == 1); 1398 err = control->error; 1399 kfree(control); 1400 return err; 1401 } 1402 1403 1404 /* 1405 * DLCI level handling: Needs krefs 1406 */ 1407 1408 /* 1409 * State transitions and timers 1410 */ 1411 1412 /** 1413 * gsm_dlci_close - a DLCI has closed 1414 * @dlci: DLCI that closed 1415 * 1416 * Perform processing when moving a DLCI into closed state. If there 1417 * is an attached tty this is hung up 1418 */ 1419 1420 static void gsm_dlci_close(struct gsm_dlci *dlci) 1421 { 1422 del_timer(&dlci->t1); 1423 if (debug & 8) 1424 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1425 dlci->state = DLCI_CLOSED; 1426 if (dlci->addr != 0) { 1427 tty_port_tty_hangup(&dlci->port, false); 1428 kfifo_reset(&dlci->fifo); 1429 } else 1430 dlci->gsm->dead = true; 1431 wake_up(&dlci->gsm->event); 1432 /* A DLCI 0 close is a MUX termination so we need to kick that 1433 back to userspace somehow */ 1434 } 1435 1436 /** 1437 * gsm_dlci_open - a DLCI has opened 1438 * @dlci: DLCI that opened 1439 * 1440 * Perform processing when moving a DLCI into open state. 1441 */ 1442 1443 static void gsm_dlci_open(struct gsm_dlci *dlci) 1444 { 1445 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1446 open -> open */ 1447 del_timer(&dlci->t1); 1448 /* This will let a tty open continue */ 1449 dlci->state = DLCI_OPEN; 1450 if (debug & 8) 1451 pr_debug("DLCI %d goes open.\n", dlci->addr); 1452 wake_up(&dlci->gsm->event); 1453 } 1454 1455 /** 1456 * gsm_dlci_t1 - T1 timer expiry 1457 * @dlci: DLCI that opened 1458 * 1459 * The T1 timer handles retransmits of control frames (essentially of 1460 * SABM and DISC). We resend the command until the retry count runs out 1461 * in which case an opening port goes back to closed and a closing port 1462 * is simply put into closed state (any further frames from the other 1463 * end will get a DM response) 1464 * 1465 * Some control dlci can stay in ADM mode with other dlci working just 1466 * fine. In that case we can just keep the control dlci open after the 1467 * DLCI_OPENING retries time out. 1468 */ 1469 1470 static void gsm_dlci_t1(struct timer_list *t) 1471 { 1472 struct gsm_dlci *dlci = from_timer(dlci, t, t1); 1473 struct gsm_mux *gsm = dlci->gsm; 1474 1475 switch (dlci->state) { 1476 case DLCI_OPENING: 1477 dlci->retries--; 1478 if (dlci->retries) { 1479 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1480 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1481 } else if (!dlci->addr && gsm->control == (DM | PF)) { 1482 if (debug & 8) 1483 pr_info("DLCI %d opening in ADM mode.\n", 1484 dlci->addr); 1485 dlci->mode = DLCI_MODE_ADM; 1486 gsm_dlci_open(dlci); 1487 } else { 1488 gsm_dlci_close(dlci); 1489 } 1490 1491 break; 1492 case DLCI_CLOSING: 1493 dlci->retries--; 1494 if (dlci->retries) { 1495 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1496 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1497 } else 1498 gsm_dlci_close(dlci); 1499 break; 1500 default: 1501 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state); 1502 break; 1503 } 1504 } 1505 1506 /** 1507 * gsm_dlci_begin_open - start channel open procedure 1508 * @dlci: DLCI to open 1509 * 1510 * Commence opening a DLCI from the Linux side. We issue SABM messages 1511 * to the modem which should then reply with a UA or ADM, at which point 1512 * we will move into open state. Opening is done asynchronously with retry 1513 * running off timers and the responses. 1514 */ 1515 1516 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1517 { 1518 struct gsm_mux *gsm = dlci->gsm; 1519 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1520 return; 1521 dlci->retries = gsm->n2; 1522 dlci->state = DLCI_OPENING; 1523 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1524 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1525 } 1526 1527 /** 1528 * gsm_dlci_begin_close - start channel open procedure 1529 * @dlci: DLCI to open 1530 * 1531 * Commence closing a DLCI from the Linux side. We issue DISC messages 1532 * to the modem which should then reply with a UA, at which point we 1533 * will move into closed state. Closing is done asynchronously with retry 1534 * off timers. We may also receive a DM reply from the other end which 1535 * indicates the channel was already closed. 1536 */ 1537 1538 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1539 { 1540 struct gsm_mux *gsm = dlci->gsm; 1541 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1542 return; 1543 dlci->retries = gsm->n2; 1544 dlci->state = DLCI_CLOSING; 1545 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1546 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1547 } 1548 1549 /** 1550 * gsm_dlci_data - data arrived 1551 * @dlci: channel 1552 * @data: block of bytes received 1553 * @len: length of received block 1554 * 1555 * A UI or UIH frame has arrived which contains data for a channel 1556 * other than the control channel. If the relevant virtual tty is 1557 * open we shovel the bits down it, if not we drop them. 1558 */ 1559 1560 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) 1561 { 1562 /* krefs .. */ 1563 struct tty_port *port = &dlci->port; 1564 struct tty_struct *tty; 1565 unsigned int modem = 0; 1566 int len = clen; 1567 1568 if (debug & 16) 1569 pr_debug("%d bytes for tty\n", len); 1570 switch (dlci->adaption) { 1571 /* Unsupported types */ 1572 case 4: /* Packetised interruptible data */ 1573 break; 1574 case 3: /* Packetised uininterruptible voice/data */ 1575 break; 1576 case 2: /* Asynchronous serial with line state in each frame */ 1577 while (gsm_read_ea(&modem, *data++) == 0) { 1578 len--; 1579 if (len == 0) 1580 return; 1581 } 1582 tty = tty_port_tty_get(port); 1583 if (tty) { 1584 gsm_process_modem(tty, dlci, modem, clen); 1585 tty_kref_put(tty); 1586 } 1587 /* Fall through */ 1588 case 1: /* Line state will go via DLCI 0 controls only */ 1589 default: 1590 tty_insert_flip_string(port, data, len); 1591 tty_flip_buffer_push(port); 1592 } 1593 } 1594 1595 /** 1596 * gsm_dlci_control - data arrived on control channel 1597 * @dlci: channel 1598 * @data: block of bytes received 1599 * @len: length of received block 1600 * 1601 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1602 * control channel. This should contain a command EA followed by 1603 * control data bytes. The command EA contains a command/response bit 1604 * and we divide up the work accordingly. 1605 */ 1606 1607 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) 1608 { 1609 /* See what command is involved */ 1610 unsigned int command = 0; 1611 while (len-- > 0) { 1612 if (gsm_read_ea(&command, *data++) == 1) { 1613 int clen = *data++; 1614 len--; 1615 /* FIXME: this is properly an EA */ 1616 clen >>= 1; 1617 /* Malformed command ? */ 1618 if (clen > len) 1619 return; 1620 if (command & 1) 1621 gsm_control_message(dlci->gsm, command, 1622 data, clen); 1623 else 1624 gsm_control_response(dlci->gsm, command, 1625 data, clen); 1626 return; 1627 } 1628 } 1629 } 1630 1631 /* 1632 * Allocate/Free DLCI channels 1633 */ 1634 1635 /** 1636 * gsm_dlci_alloc - allocate a DLCI 1637 * @gsm: GSM mux 1638 * @addr: address of the DLCI 1639 * 1640 * Allocate and install a new DLCI object into the GSM mux. 1641 * 1642 * FIXME: review locking races 1643 */ 1644 1645 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1646 { 1647 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1648 if (dlci == NULL) 1649 return NULL; 1650 spin_lock_init(&dlci->lock); 1651 mutex_init(&dlci->mutex); 1652 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) { 1653 kfree(dlci); 1654 return NULL; 1655 } 1656 1657 skb_queue_head_init(&dlci->skb_list); 1658 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 1659 tty_port_init(&dlci->port); 1660 dlci->port.ops = &gsm_port_ops; 1661 dlci->gsm = gsm; 1662 dlci->addr = addr; 1663 dlci->adaption = gsm->adaption; 1664 dlci->state = DLCI_CLOSED; 1665 if (addr) 1666 dlci->data = gsm_dlci_data; 1667 else 1668 dlci->data = gsm_dlci_command; 1669 gsm->dlci[addr] = dlci; 1670 return dlci; 1671 } 1672 1673 /** 1674 * gsm_dlci_free - free DLCI 1675 * @dlci: DLCI to free 1676 * 1677 * Free up a DLCI. 1678 * 1679 * Can sleep. 1680 */ 1681 static void gsm_dlci_free(struct tty_port *port) 1682 { 1683 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1684 1685 del_timer_sync(&dlci->t1); 1686 dlci->gsm->dlci[dlci->addr] = NULL; 1687 kfifo_free(&dlci->fifo); 1688 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1689 dev_kfree_skb(dlci->skb); 1690 kfree(dlci); 1691 } 1692 1693 static inline void dlci_get(struct gsm_dlci *dlci) 1694 { 1695 tty_port_get(&dlci->port); 1696 } 1697 1698 static inline void dlci_put(struct gsm_dlci *dlci) 1699 { 1700 tty_port_put(&dlci->port); 1701 } 1702 1703 static void gsm_destroy_network(struct gsm_dlci *dlci); 1704 1705 /** 1706 * gsm_dlci_release - release DLCI 1707 * @dlci: DLCI to destroy 1708 * 1709 * Release a DLCI. Actual free is deferred until either 1710 * mux is closed or tty is closed - whichever is last. 1711 * 1712 * Can sleep. 1713 */ 1714 static void gsm_dlci_release(struct gsm_dlci *dlci) 1715 { 1716 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1717 if (tty) { 1718 mutex_lock(&dlci->mutex); 1719 gsm_destroy_network(dlci); 1720 mutex_unlock(&dlci->mutex); 1721 1722 tty_hangup(tty); 1723 1724 tty_port_tty_set(&dlci->port, NULL); 1725 tty_kref_put(tty); 1726 } 1727 dlci->state = DLCI_CLOSED; 1728 dlci_put(dlci); 1729 } 1730 1731 /* 1732 * LAPBish link layer logic 1733 */ 1734 1735 /** 1736 * gsm_queue - a GSM frame is ready to process 1737 * @gsm: pointer to our gsm mux 1738 * 1739 * At this point in time a frame has arrived and been demangled from 1740 * the line encoding. All the differences between the encodings have 1741 * been handled below us and the frame is unpacked into the structures. 1742 * The fcs holds the header FCS but any data FCS must be added here. 1743 */ 1744 1745 static void gsm_queue(struct gsm_mux *gsm) 1746 { 1747 struct gsm_dlci *dlci; 1748 u8 cr; 1749 int address; 1750 /* We have to sneak a look at the packet body to do the FCS. 1751 A somewhat layering violation in the spec */ 1752 1753 if ((gsm->control & ~PF) == UI) 1754 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1755 if (gsm->encoding == 0) { 1756 /* WARNING: gsm->received_fcs is used for 1757 gsm->encoding = 0 only. 1758 In this case it contain the last piece of data 1759 required to generate final CRC */ 1760 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1761 } 1762 if (gsm->fcs != GOOD_FCS) { 1763 gsm->bad_fcs++; 1764 if (debug & 4) 1765 pr_debug("BAD FCS %02x\n", gsm->fcs); 1766 return; 1767 } 1768 address = gsm->address >> 1; 1769 if (address >= NUM_DLCI) 1770 goto invalid; 1771 1772 cr = gsm->address & 1; /* C/R bit */ 1773 1774 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1775 1776 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1777 dlci = gsm->dlci[address]; 1778 1779 switch (gsm->control) { 1780 case SABM|PF: 1781 if (cr == 0) 1782 goto invalid; 1783 if (dlci == NULL) 1784 dlci = gsm_dlci_alloc(gsm, address); 1785 if (dlci == NULL) 1786 return; 1787 if (dlci->dead) 1788 gsm_response(gsm, address, DM); 1789 else { 1790 gsm_response(gsm, address, UA); 1791 gsm_dlci_open(dlci); 1792 } 1793 break; 1794 case DISC|PF: 1795 if (cr == 0) 1796 goto invalid; 1797 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1798 gsm_response(gsm, address, DM); 1799 return; 1800 } 1801 /* Real close complete */ 1802 gsm_response(gsm, address, UA); 1803 gsm_dlci_close(dlci); 1804 break; 1805 case UA: 1806 case UA|PF: 1807 if (cr == 0 || dlci == NULL) 1808 break; 1809 switch (dlci->state) { 1810 case DLCI_CLOSING: 1811 gsm_dlci_close(dlci); 1812 break; 1813 case DLCI_OPENING: 1814 gsm_dlci_open(dlci); 1815 break; 1816 default: 1817 pr_debug("%s: unhandled state: %d\n", __func__, 1818 dlci->state); 1819 break; 1820 } 1821 break; 1822 case DM: /* DM can be valid unsolicited */ 1823 case DM|PF: 1824 if (cr) 1825 goto invalid; 1826 if (dlci == NULL) 1827 return; 1828 gsm_dlci_close(dlci); 1829 break; 1830 case UI: 1831 case UI|PF: 1832 case UIH: 1833 case UIH|PF: 1834 #if 0 1835 if (cr) 1836 goto invalid; 1837 #endif 1838 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1839 gsm_command(gsm, address, DM|PF); 1840 return; 1841 } 1842 dlci->data(dlci, gsm->buf, gsm->len); 1843 break; 1844 default: 1845 goto invalid; 1846 } 1847 return; 1848 invalid: 1849 gsm->malformed++; 1850 return; 1851 } 1852 1853 1854 /** 1855 * gsm0_receive - perform processing for non-transparency 1856 * @gsm: gsm data for this ldisc instance 1857 * @c: character 1858 * 1859 * Receive bytes in gsm mode 0 1860 */ 1861 1862 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1863 { 1864 unsigned int len; 1865 1866 switch (gsm->state) { 1867 case GSM_SEARCH: /* SOF marker */ 1868 if (c == GSM0_SOF) { 1869 gsm->state = GSM_ADDRESS; 1870 gsm->address = 0; 1871 gsm->len = 0; 1872 gsm->fcs = INIT_FCS; 1873 } 1874 break; 1875 case GSM_ADDRESS: /* Address EA */ 1876 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1877 if (gsm_read_ea(&gsm->address, c)) 1878 gsm->state = GSM_CONTROL; 1879 break; 1880 case GSM_CONTROL: /* Control Byte */ 1881 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1882 gsm->control = c; 1883 gsm->state = GSM_LEN0; 1884 break; 1885 case GSM_LEN0: /* Length EA */ 1886 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1887 if (gsm_read_ea(&gsm->len, c)) { 1888 if (gsm->len > gsm->mru) { 1889 gsm->bad_size++; 1890 gsm->state = GSM_SEARCH; 1891 break; 1892 } 1893 gsm->count = 0; 1894 if (!gsm->len) 1895 gsm->state = GSM_FCS; 1896 else 1897 gsm->state = GSM_DATA; 1898 break; 1899 } 1900 gsm->state = GSM_LEN1; 1901 break; 1902 case GSM_LEN1: 1903 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1904 len = c; 1905 gsm->len |= len << 7; 1906 if (gsm->len > gsm->mru) { 1907 gsm->bad_size++; 1908 gsm->state = GSM_SEARCH; 1909 break; 1910 } 1911 gsm->count = 0; 1912 if (!gsm->len) 1913 gsm->state = GSM_FCS; 1914 else 1915 gsm->state = GSM_DATA; 1916 break; 1917 case GSM_DATA: /* Data */ 1918 gsm->buf[gsm->count++] = c; 1919 if (gsm->count == gsm->len) 1920 gsm->state = GSM_FCS; 1921 break; 1922 case GSM_FCS: /* FCS follows the packet */ 1923 gsm->received_fcs = c; 1924 gsm_queue(gsm); 1925 gsm->state = GSM_SSOF; 1926 break; 1927 case GSM_SSOF: 1928 if (c == GSM0_SOF) { 1929 gsm->state = GSM_SEARCH; 1930 break; 1931 } 1932 break; 1933 default: 1934 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 1935 break; 1936 } 1937 } 1938 1939 /** 1940 * gsm1_receive - perform processing for non-transparency 1941 * @gsm: gsm data for this ldisc instance 1942 * @c: character 1943 * 1944 * Receive bytes in mode 1 (Advanced option) 1945 */ 1946 1947 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1948 { 1949 if (c == GSM1_SOF) { 1950 /* EOF is only valid in frame if we have got to the data state 1951 and received at least one byte (the FCS) */ 1952 if (gsm->state == GSM_DATA && gsm->count) { 1953 /* Extract the FCS */ 1954 gsm->count--; 1955 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1956 gsm->len = gsm->count; 1957 gsm_queue(gsm); 1958 gsm->state = GSM_START; 1959 return; 1960 } 1961 /* Any partial frame was a runt so go back to start */ 1962 if (gsm->state != GSM_START) { 1963 gsm->malformed++; 1964 gsm->state = GSM_START; 1965 } 1966 /* A SOF in GSM_START means we are still reading idling or 1967 framing bytes */ 1968 return; 1969 } 1970 1971 if (c == GSM1_ESCAPE) { 1972 gsm->escape = true; 1973 return; 1974 } 1975 1976 /* Only an unescaped SOF gets us out of GSM search */ 1977 if (gsm->state == GSM_SEARCH) 1978 return; 1979 1980 if (gsm->escape) { 1981 c ^= GSM1_ESCAPE_BITS; 1982 gsm->escape = false; 1983 } 1984 switch (gsm->state) { 1985 case GSM_START: /* First byte after SOF */ 1986 gsm->address = 0; 1987 gsm->state = GSM_ADDRESS; 1988 gsm->fcs = INIT_FCS; 1989 /* Fall through */ 1990 case GSM_ADDRESS: /* Address continuation */ 1991 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1992 if (gsm_read_ea(&gsm->address, c)) 1993 gsm->state = GSM_CONTROL; 1994 break; 1995 case GSM_CONTROL: /* Control Byte */ 1996 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1997 gsm->control = c; 1998 gsm->count = 0; 1999 gsm->state = GSM_DATA; 2000 break; 2001 case GSM_DATA: /* Data */ 2002 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 2003 gsm->state = GSM_OVERRUN; 2004 gsm->bad_size++; 2005 } else 2006 gsm->buf[gsm->count++] = c; 2007 break; 2008 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 2009 break; 2010 default: 2011 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 2012 break; 2013 } 2014 } 2015 2016 /** 2017 * gsm_error - handle tty error 2018 * @gsm: ldisc data 2019 * @data: byte received (may be invalid) 2020 * @flag: error received 2021 * 2022 * Handle an error in the receipt of data for a frame. Currently we just 2023 * go back to hunting for a SOF. 2024 * 2025 * FIXME: better diagnostics ? 2026 */ 2027 2028 static void gsm_error(struct gsm_mux *gsm, 2029 unsigned char data, unsigned char flag) 2030 { 2031 gsm->state = GSM_SEARCH; 2032 gsm->io_error++; 2033 } 2034 2035 static int gsm_disconnect(struct gsm_mux *gsm) 2036 { 2037 struct gsm_dlci *dlci = gsm->dlci[0]; 2038 struct gsm_control *gc; 2039 2040 if (!dlci) 2041 return 0; 2042 2043 /* In theory disconnecting DLCI 0 is sufficient but for some 2044 modems this is apparently not the case. */ 2045 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2046 if (gc) 2047 gsm_control_wait(gsm, gc); 2048 2049 del_timer_sync(&gsm->t2_timer); 2050 /* Now we are sure T2 has stopped */ 2051 2052 gsm_dlci_begin_close(dlci); 2053 wait_event_interruptible(gsm->event, 2054 dlci->state == DLCI_CLOSED); 2055 2056 if (signal_pending(current)) 2057 return -EINTR; 2058 2059 return 0; 2060 } 2061 2062 /** 2063 * gsm_cleanup_mux - generic GSM protocol cleanup 2064 * @gsm: our mux 2065 * 2066 * Clean up the bits of the mux which are the same for all framing 2067 * protocols. Remove the mux from the mux table, stop all the timers 2068 * and then shut down each device hanging up the channels as we go. 2069 */ 2070 2071 static void gsm_cleanup_mux(struct gsm_mux *gsm) 2072 { 2073 int i; 2074 struct gsm_dlci *dlci = gsm->dlci[0]; 2075 struct gsm_msg *txq, *ntxq; 2076 2077 gsm->dead = true; 2078 2079 spin_lock(&gsm_mux_lock); 2080 for (i = 0; i < MAX_MUX; i++) { 2081 if (gsm_mux[i] == gsm) { 2082 gsm_mux[i] = NULL; 2083 break; 2084 } 2085 } 2086 spin_unlock(&gsm_mux_lock); 2087 /* open failed before registering => nothing to do */ 2088 if (i == MAX_MUX) 2089 return; 2090 2091 del_timer_sync(&gsm->t2_timer); 2092 /* Now we are sure T2 has stopped */ 2093 if (dlci) 2094 dlci->dead = true; 2095 2096 /* Free up any link layer users */ 2097 mutex_lock(&gsm->mutex); 2098 for (i = 0; i < NUM_DLCI; i++) 2099 if (gsm->dlci[i]) 2100 gsm_dlci_release(gsm->dlci[i]); 2101 mutex_unlock(&gsm->mutex); 2102 /* Now wipe the queues */ 2103 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2104 kfree(txq); 2105 INIT_LIST_HEAD(&gsm->tx_list); 2106 } 2107 2108 /** 2109 * gsm_activate_mux - generic GSM setup 2110 * @gsm: our mux 2111 * 2112 * Set up the bits of the mux which are the same for all framing 2113 * protocols. Add the mux to the mux table so it can be opened and 2114 * finally kick off connecting to DLCI 0 on the modem. 2115 */ 2116 2117 static int gsm_activate_mux(struct gsm_mux *gsm) 2118 { 2119 struct gsm_dlci *dlci; 2120 int i = 0; 2121 2122 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 2123 init_waitqueue_head(&gsm->event); 2124 spin_lock_init(&gsm->control_lock); 2125 spin_lock_init(&gsm->tx_lock); 2126 2127 if (gsm->encoding == 0) 2128 gsm->receive = gsm0_receive; 2129 else 2130 gsm->receive = gsm1_receive; 2131 gsm->error = gsm_error; 2132 2133 spin_lock(&gsm_mux_lock); 2134 for (i = 0; i < MAX_MUX; i++) { 2135 if (gsm_mux[i] == NULL) { 2136 gsm->num = i; 2137 gsm_mux[i] = gsm; 2138 break; 2139 } 2140 } 2141 spin_unlock(&gsm_mux_lock); 2142 if (i == MAX_MUX) 2143 return -EBUSY; 2144 2145 dlci = gsm_dlci_alloc(gsm, 0); 2146 if (dlci == NULL) 2147 return -ENOMEM; 2148 gsm->dead = false; /* Tty opens are now permissible */ 2149 return 0; 2150 } 2151 2152 /** 2153 * gsm_free_mux - free up a mux 2154 * @mux: mux to free 2155 * 2156 * Dispose of allocated resources for a dead mux 2157 */ 2158 static void gsm_free_mux(struct gsm_mux *gsm) 2159 { 2160 kfree(gsm->txframe); 2161 kfree(gsm->buf); 2162 kfree(gsm); 2163 } 2164 2165 /** 2166 * gsm_free_muxr - free up a mux 2167 * @mux: mux to free 2168 * 2169 * Dispose of allocated resources for a dead mux 2170 */ 2171 static void gsm_free_muxr(struct kref *ref) 2172 { 2173 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2174 gsm_free_mux(gsm); 2175 } 2176 2177 static inline void mux_get(struct gsm_mux *gsm) 2178 { 2179 kref_get(&gsm->ref); 2180 } 2181 2182 static inline void mux_put(struct gsm_mux *gsm) 2183 { 2184 kref_put(&gsm->ref, gsm_free_muxr); 2185 } 2186 2187 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) 2188 { 2189 return gsm->num * NUM_DLCI; 2190 } 2191 2192 static inline unsigned int mux_line_to_num(unsigned int line) 2193 { 2194 return line / NUM_DLCI; 2195 } 2196 2197 /** 2198 * gsm_alloc_mux - allocate a mux 2199 * 2200 * Creates a new mux ready for activation. 2201 */ 2202 2203 static struct gsm_mux *gsm_alloc_mux(void) 2204 { 2205 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2206 if (gsm == NULL) 2207 return NULL; 2208 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2209 if (gsm->buf == NULL) { 2210 kfree(gsm); 2211 return NULL; 2212 } 2213 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2214 if (gsm->txframe == NULL) { 2215 kfree(gsm->buf); 2216 kfree(gsm); 2217 return NULL; 2218 } 2219 spin_lock_init(&gsm->lock); 2220 mutex_init(&gsm->mutex); 2221 kref_init(&gsm->ref); 2222 INIT_LIST_HEAD(&gsm->tx_list); 2223 2224 gsm->t1 = T1; 2225 gsm->t2 = T2; 2226 gsm->n2 = N2; 2227 gsm->ftype = UIH; 2228 gsm->adaption = 1; 2229 gsm->encoding = 1; 2230 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2231 gsm->mtu = 64; 2232 gsm->dead = true; /* Avoid early tty opens */ 2233 2234 return gsm; 2235 } 2236 2237 static void gsm_copy_config_values(struct gsm_mux *gsm, 2238 struct gsm_config *c) 2239 { 2240 memset(c, 0, sizeof(*c)); 2241 c->adaption = gsm->adaption; 2242 c->encapsulation = gsm->encoding; 2243 c->initiator = gsm->initiator; 2244 c->t1 = gsm->t1; 2245 c->t2 = gsm->t2; 2246 c->t3 = 0; /* Not supported */ 2247 c->n2 = gsm->n2; 2248 if (gsm->ftype == UIH) 2249 c->i = 1; 2250 else 2251 c->i = 2; 2252 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); 2253 c->mru = gsm->mru; 2254 c->mtu = gsm->mtu; 2255 c->k = 0; 2256 } 2257 2258 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 2259 { 2260 int need_close = 0; 2261 int need_restart = 0; 2262 2263 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2264 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2265 return -EOPNOTSUPP; 2266 /* Check the MRU/MTU range looks sane */ 2267 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2268 return -EINVAL; 2269 if (c->n2 < 3) 2270 return -EINVAL; 2271 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2272 return -EINVAL; 2273 if (c->initiator > 1) 2274 return -EINVAL; 2275 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2276 return -EINVAL; 2277 /* 2278 * See what is needed for reconfiguration 2279 */ 2280 2281 /* Timing fields */ 2282 if (c->t1 != 0 && c->t1 != gsm->t1) 2283 need_restart = 1; 2284 if (c->t2 != 0 && c->t2 != gsm->t2) 2285 need_restart = 1; 2286 if (c->encapsulation != gsm->encoding) 2287 need_restart = 1; 2288 if (c->adaption != gsm->adaption) 2289 need_restart = 1; 2290 /* Requires care */ 2291 if (c->initiator != gsm->initiator) 2292 need_close = 1; 2293 if (c->mru != gsm->mru) 2294 need_restart = 1; 2295 if (c->mtu != gsm->mtu) 2296 need_restart = 1; 2297 2298 /* 2299 * Close down what is needed, restart and initiate the new 2300 * configuration 2301 */ 2302 2303 if (need_close || need_restart) { 2304 int ret; 2305 2306 ret = gsm_disconnect(gsm); 2307 2308 if (ret) 2309 return ret; 2310 } 2311 if (need_restart) 2312 gsm_cleanup_mux(gsm); 2313 2314 gsm->initiator = c->initiator; 2315 gsm->mru = c->mru; 2316 gsm->mtu = c->mtu; 2317 gsm->encoding = c->encapsulation; 2318 gsm->adaption = c->adaption; 2319 gsm->n2 = c->n2; 2320 2321 if (c->i == 1) 2322 gsm->ftype = UIH; 2323 else if (c->i == 2) 2324 gsm->ftype = UI; 2325 2326 if (c->t1) 2327 gsm->t1 = c->t1; 2328 if (c->t2) 2329 gsm->t2 = c->t2; 2330 2331 /* 2332 * FIXME: We need to separate activation/deactivation from adding 2333 * and removing from the mux array 2334 */ 2335 if (need_restart) 2336 gsm_activate_mux(gsm); 2337 if (gsm->initiator && need_close) 2338 gsm_dlci_begin_open(gsm->dlci[0]); 2339 return 0; 2340 } 2341 2342 /** 2343 * gsmld_output - write to link 2344 * @gsm: our mux 2345 * @data: bytes to output 2346 * @len: size 2347 * 2348 * Write a block of data from the GSM mux to the data channel. This 2349 * will eventually be serialized from above but at the moment isn't. 2350 */ 2351 2352 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2353 { 2354 if (tty_write_room(gsm->tty) < len) { 2355 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2356 return -ENOSPC; 2357 } 2358 if (debug & 4) 2359 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2360 data, len); 2361 gsm->tty->ops->write(gsm->tty, data, len); 2362 return len; 2363 } 2364 2365 /** 2366 * gsmld_attach_gsm - mode set up 2367 * @tty: our tty structure 2368 * @gsm: our mux 2369 * 2370 * Set up the MUX for basic mode and commence connecting to the 2371 * modem. Currently called from the line discipline set up but 2372 * will need moving to an ioctl path. 2373 */ 2374 2375 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2376 { 2377 unsigned int base; 2378 int ret, i; 2379 2380 gsm->tty = tty_kref_get(tty); 2381 gsm->output = gsmld_output; 2382 ret = gsm_activate_mux(gsm); 2383 if (ret != 0) 2384 tty_kref_put(gsm->tty); 2385 else { 2386 /* Don't register device 0 - this is the control channel and not 2387 a usable tty interface */ 2388 base = mux_num_to_base(gsm); /* Base for this MUX */ 2389 for (i = 1; i < NUM_DLCI; i++) 2390 tty_register_device(gsm_tty_driver, base + i, NULL); 2391 } 2392 return ret; 2393 } 2394 2395 2396 /** 2397 * gsmld_detach_gsm - stop doing 0710 mux 2398 * @tty: tty attached to the mux 2399 * @gsm: mux 2400 * 2401 * Shutdown and then clean up the resources used by the line discipline 2402 */ 2403 2404 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2405 { 2406 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */ 2407 int i; 2408 2409 WARN_ON(tty != gsm->tty); 2410 for (i = 1; i < NUM_DLCI; i++) 2411 tty_unregister_device(gsm_tty_driver, base + i); 2412 gsm_cleanup_mux(gsm); 2413 tty_kref_put(gsm->tty); 2414 gsm->tty = NULL; 2415 } 2416 2417 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2418 char *fp, int count) 2419 { 2420 struct gsm_mux *gsm = tty->disc_data; 2421 const unsigned char *dp; 2422 char *f; 2423 int i; 2424 char flags = TTY_NORMAL; 2425 2426 if (debug & 4) 2427 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2428 cp, count); 2429 2430 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2431 if (f) 2432 flags = *f++; 2433 switch (flags) { 2434 case TTY_NORMAL: 2435 gsm->receive(gsm, *dp); 2436 break; 2437 case TTY_OVERRUN: 2438 case TTY_BREAK: 2439 case TTY_PARITY: 2440 case TTY_FRAME: 2441 gsm->error(gsm, *dp, flags); 2442 break; 2443 default: 2444 WARN_ONCE(1, "%s: unknown flag %d\n", 2445 tty_name(tty), flags); 2446 break; 2447 } 2448 } 2449 /* FASYNC if needed ? */ 2450 /* If clogged call tty_throttle(tty); */ 2451 } 2452 2453 /** 2454 * gsmld_flush_buffer - clean input queue 2455 * @tty: terminal device 2456 * 2457 * Flush the input buffer. Called when the line discipline is 2458 * being closed, when the tty layer wants the buffer flushed (eg 2459 * at hangup). 2460 */ 2461 2462 static void gsmld_flush_buffer(struct tty_struct *tty) 2463 { 2464 } 2465 2466 /** 2467 * gsmld_close - close the ldisc for this tty 2468 * @tty: device 2469 * 2470 * Called from the terminal layer when this line discipline is 2471 * being shut down, either because of a close or becsuse of a 2472 * discipline change. The function will not be called while other 2473 * ldisc methods are in progress. 2474 */ 2475 2476 static void gsmld_close(struct tty_struct *tty) 2477 { 2478 struct gsm_mux *gsm = tty->disc_data; 2479 2480 gsmld_detach_gsm(tty, gsm); 2481 2482 gsmld_flush_buffer(tty); 2483 /* Do other clean up here */ 2484 mux_put(gsm); 2485 } 2486 2487 /** 2488 * gsmld_open - open an ldisc 2489 * @tty: terminal to open 2490 * 2491 * Called when this line discipline is being attached to the 2492 * terminal device. Can sleep. Called serialized so that no 2493 * other events will occur in parallel. No further open will occur 2494 * until a close. 2495 */ 2496 2497 static int gsmld_open(struct tty_struct *tty) 2498 { 2499 struct gsm_mux *gsm; 2500 int ret; 2501 2502 if (tty->ops->write == NULL) 2503 return -EINVAL; 2504 2505 /* Attach our ldisc data */ 2506 gsm = gsm_alloc_mux(); 2507 if (gsm == NULL) 2508 return -ENOMEM; 2509 2510 tty->disc_data = gsm; 2511 tty->receive_room = 65536; 2512 2513 /* Attach the initial passive connection */ 2514 gsm->encoding = 1; 2515 2516 ret = gsmld_attach_gsm(tty, gsm); 2517 if (ret != 0) { 2518 gsm_cleanup_mux(gsm); 2519 mux_put(gsm); 2520 } 2521 return ret; 2522 } 2523 2524 /** 2525 * gsmld_write_wakeup - asynchronous I/O notifier 2526 * @tty: tty device 2527 * 2528 * Required for the ptys, serial driver etc. since processes 2529 * that attach themselves to the master and rely on ASYNC 2530 * IO must be woken up 2531 */ 2532 2533 static void gsmld_write_wakeup(struct tty_struct *tty) 2534 { 2535 struct gsm_mux *gsm = tty->disc_data; 2536 unsigned long flags; 2537 2538 /* Queue poll */ 2539 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2540 spin_lock_irqsave(&gsm->tx_lock, flags); 2541 gsm_data_kick(gsm, NULL); 2542 if (gsm->tx_bytes < TX_THRESH_LO) { 2543 gsm_dlci_data_sweep(gsm); 2544 } 2545 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2546 } 2547 2548 /** 2549 * gsmld_read - read function for tty 2550 * @tty: tty device 2551 * @file: file object 2552 * @buf: userspace buffer pointer 2553 * @nr: size of I/O 2554 * 2555 * Perform reads for the line discipline. We are guaranteed that the 2556 * line discipline will not be closed under us but we may get multiple 2557 * parallel readers and must handle this ourselves. We may also get 2558 * a hangup. Always called in user context, may sleep. 2559 * 2560 * This code must be sure never to sleep through a hangup. 2561 */ 2562 2563 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2564 unsigned char __user *buf, size_t nr) 2565 { 2566 return -EOPNOTSUPP; 2567 } 2568 2569 /** 2570 * gsmld_write - write function for tty 2571 * @tty: tty device 2572 * @file: file object 2573 * @buf: userspace buffer pointer 2574 * @nr: size of I/O 2575 * 2576 * Called when the owner of the device wants to send a frame 2577 * itself (or some other control data). The data is transferred 2578 * as-is and must be properly framed and checksummed as appropriate 2579 * by userspace. Frames are either sent whole or not at all as this 2580 * avoids pain user side. 2581 */ 2582 2583 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2584 const unsigned char *buf, size_t nr) 2585 { 2586 int space = tty_write_room(tty); 2587 if (space >= nr) 2588 return tty->ops->write(tty, buf, nr); 2589 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2590 return -ENOBUFS; 2591 } 2592 2593 /** 2594 * gsmld_poll - poll method for N_GSM0710 2595 * @tty: terminal device 2596 * @file: file accessing it 2597 * @wait: poll table 2598 * 2599 * Called when the line discipline is asked to poll() for data or 2600 * for special events. This code is not serialized with respect to 2601 * other events save open/close. 2602 * 2603 * This code must be sure never to sleep through a hangup. 2604 * Called without the kernel lock held - fine 2605 */ 2606 2607 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 2608 poll_table *wait) 2609 { 2610 __poll_t mask = 0; 2611 struct gsm_mux *gsm = tty->disc_data; 2612 2613 poll_wait(file, &tty->read_wait, wait); 2614 poll_wait(file, &tty->write_wait, wait); 2615 if (tty_hung_up_p(file)) 2616 mask |= EPOLLHUP; 2617 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2618 mask |= EPOLLOUT | EPOLLWRNORM; 2619 if (gsm->dead) 2620 mask |= EPOLLHUP; 2621 return mask; 2622 } 2623 2624 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2625 unsigned int cmd, unsigned long arg) 2626 { 2627 struct gsm_config c; 2628 struct gsm_mux *gsm = tty->disc_data; 2629 unsigned int base; 2630 2631 switch (cmd) { 2632 case GSMIOC_GETCONF: 2633 gsm_copy_config_values(gsm, &c); 2634 if (copy_to_user((void __user *)arg, &c, sizeof(c))) 2635 return -EFAULT; 2636 return 0; 2637 case GSMIOC_SETCONF: 2638 if (copy_from_user(&c, (void __user *)arg, sizeof(c))) 2639 return -EFAULT; 2640 return gsm_config(gsm, &c); 2641 case GSMIOC_GETFIRST: 2642 base = mux_num_to_base(gsm); 2643 return put_user(base + 1, (__u32 __user *)arg); 2644 default: 2645 return n_tty_ioctl_helper(tty, file, cmd, arg); 2646 } 2647 } 2648 2649 /* 2650 * Network interface 2651 * 2652 */ 2653 2654 static int gsm_mux_net_open(struct net_device *net) 2655 { 2656 pr_debug("%s called\n", __func__); 2657 netif_start_queue(net); 2658 return 0; 2659 } 2660 2661 static int gsm_mux_net_close(struct net_device *net) 2662 { 2663 netif_stop_queue(net); 2664 return 0; 2665 } 2666 2667 static void dlci_net_free(struct gsm_dlci *dlci) 2668 { 2669 if (!dlci->net) { 2670 WARN_ON(1); 2671 return; 2672 } 2673 dlci->adaption = dlci->prev_adaption; 2674 dlci->data = dlci->prev_data; 2675 free_netdev(dlci->net); 2676 dlci->net = NULL; 2677 } 2678 static void net_free(struct kref *ref) 2679 { 2680 struct gsm_mux_net *mux_net; 2681 struct gsm_dlci *dlci; 2682 2683 mux_net = container_of(ref, struct gsm_mux_net, ref); 2684 dlci = mux_net->dlci; 2685 2686 if (dlci->net) { 2687 unregister_netdev(dlci->net); 2688 dlci_net_free(dlci); 2689 } 2690 } 2691 2692 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2693 { 2694 kref_get(&mux_net->ref); 2695 } 2696 2697 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2698 { 2699 kref_put(&mux_net->ref, net_free); 2700 } 2701 2702 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, 2703 struct net_device *net) 2704 { 2705 struct gsm_mux_net *mux_net = netdev_priv(net); 2706 struct gsm_dlci *dlci = mux_net->dlci; 2707 muxnet_get(mux_net); 2708 2709 skb_queue_head(&dlci->skb_list, skb); 2710 net->stats.tx_packets++; 2711 net->stats.tx_bytes += skb->len; 2712 gsm_dlci_data_kick(dlci); 2713 /* And tell the kernel when the last transmit started. */ 2714 netif_trans_update(net); 2715 muxnet_put(mux_net); 2716 return NETDEV_TX_OK; 2717 } 2718 2719 /* called when a packet did not ack after watchdogtimeout */ 2720 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) 2721 { 2722 /* Tell syslog we are hosed. */ 2723 dev_dbg(&net->dev, "Tx timed out.\n"); 2724 2725 /* Update statistics */ 2726 net->stats.tx_errors++; 2727 } 2728 2729 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2730 const unsigned char *in_buf, int size) 2731 { 2732 struct net_device *net = dlci->net; 2733 struct sk_buff *skb; 2734 struct gsm_mux_net *mux_net = netdev_priv(net); 2735 muxnet_get(mux_net); 2736 2737 /* Allocate an sk_buff */ 2738 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2739 if (!skb) { 2740 /* We got no receive buffer. */ 2741 net->stats.rx_dropped++; 2742 muxnet_put(mux_net); 2743 return; 2744 } 2745 skb_reserve(skb, NET_IP_ALIGN); 2746 skb_put_data(skb, in_buf, size); 2747 2748 skb->dev = net; 2749 skb->protocol = htons(ETH_P_IP); 2750 2751 /* Ship it off to the kernel */ 2752 netif_rx(skb); 2753 2754 /* update out statistics */ 2755 net->stats.rx_packets++; 2756 net->stats.rx_bytes += size; 2757 muxnet_put(mux_net); 2758 return; 2759 } 2760 2761 static void gsm_mux_net_init(struct net_device *net) 2762 { 2763 static const struct net_device_ops gsm_netdev_ops = { 2764 .ndo_open = gsm_mux_net_open, 2765 .ndo_stop = gsm_mux_net_close, 2766 .ndo_start_xmit = gsm_mux_net_start_xmit, 2767 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2768 }; 2769 2770 net->netdev_ops = &gsm_netdev_ops; 2771 2772 /* fill in the other fields */ 2773 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2774 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2775 net->type = ARPHRD_NONE; 2776 net->tx_queue_len = 10; 2777 } 2778 2779 2780 /* caller holds the dlci mutex */ 2781 static void gsm_destroy_network(struct gsm_dlci *dlci) 2782 { 2783 struct gsm_mux_net *mux_net; 2784 2785 pr_debug("destroy network interface\n"); 2786 if (!dlci->net) 2787 return; 2788 mux_net = netdev_priv(dlci->net); 2789 muxnet_put(mux_net); 2790 } 2791 2792 2793 /* caller holds the dlci mutex */ 2794 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2795 { 2796 char *netname; 2797 int retval = 0; 2798 struct net_device *net; 2799 struct gsm_mux_net *mux_net; 2800 2801 if (!capable(CAP_NET_ADMIN)) 2802 return -EPERM; 2803 2804 /* Already in a non tty mode */ 2805 if (dlci->adaption > 2) 2806 return -EBUSY; 2807 2808 if (nc->protocol != htons(ETH_P_IP)) 2809 return -EPROTONOSUPPORT; 2810 2811 if (nc->adaption != 3 && nc->adaption != 4) 2812 return -EPROTONOSUPPORT; 2813 2814 pr_debug("create network interface\n"); 2815 2816 netname = "gsm%d"; 2817 if (nc->if_name[0] != '\0') 2818 netname = nc->if_name; 2819 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 2820 NET_NAME_UNKNOWN, gsm_mux_net_init); 2821 if (!net) { 2822 pr_err("alloc_netdev failed\n"); 2823 return -ENOMEM; 2824 } 2825 net->mtu = dlci->gsm->mtu; 2826 net->min_mtu = 8; 2827 net->max_mtu = dlci->gsm->mtu; 2828 mux_net = netdev_priv(net); 2829 mux_net->dlci = dlci; 2830 kref_init(&mux_net->ref); 2831 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2832 2833 /* reconfigure dlci for network */ 2834 dlci->prev_adaption = dlci->adaption; 2835 dlci->prev_data = dlci->data; 2836 dlci->adaption = nc->adaption; 2837 dlci->data = gsm_mux_rx_netchar; 2838 dlci->net = net; 2839 2840 pr_debug("register netdev\n"); 2841 retval = register_netdev(net); 2842 if (retval) { 2843 pr_err("network register fail %d\n", retval); 2844 dlci_net_free(dlci); 2845 return retval; 2846 } 2847 return net->ifindex; /* return network index */ 2848 } 2849 2850 /* Line discipline for real tty */ 2851 static struct tty_ldisc_ops tty_ldisc_packet = { 2852 .owner = THIS_MODULE, 2853 .magic = TTY_LDISC_MAGIC, 2854 .name = "n_gsm", 2855 .open = gsmld_open, 2856 .close = gsmld_close, 2857 .flush_buffer = gsmld_flush_buffer, 2858 .read = gsmld_read, 2859 .write = gsmld_write, 2860 .ioctl = gsmld_ioctl, 2861 .poll = gsmld_poll, 2862 .receive_buf = gsmld_receive_buf, 2863 .write_wakeup = gsmld_write_wakeup 2864 }; 2865 2866 /* 2867 * Virtual tty side 2868 */ 2869 2870 #define TX_SIZE 512 2871 2872 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2873 { 2874 u8 modembits[5]; 2875 struct gsm_control *ctrl; 2876 int len = 2; 2877 2878 if (brk) 2879 len++; 2880 2881 modembits[0] = len << 1 | EA; /* Data bytes */ 2882 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2883 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2884 if (brk) 2885 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2886 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2887 if (ctrl == NULL) 2888 return -ENOMEM; 2889 return gsm_control_wait(dlci->gsm, ctrl); 2890 } 2891 2892 static int gsm_carrier_raised(struct tty_port *port) 2893 { 2894 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2895 struct gsm_mux *gsm = dlci->gsm; 2896 2897 /* Not yet open so no carrier info */ 2898 if (dlci->state != DLCI_OPEN) 2899 return 0; 2900 if (debug & 2) 2901 return 1; 2902 2903 /* 2904 * Basic mode with control channel in ADM mode may not respond 2905 * to CMD_MSC at all and modem_rx is empty. 2906 */ 2907 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM && 2908 !dlci->modem_rx) 2909 return 1; 2910 2911 return dlci->modem_rx & TIOCM_CD; 2912 } 2913 2914 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2915 { 2916 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2917 unsigned int modem_tx = dlci->modem_tx; 2918 if (onoff) 2919 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2920 else 2921 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2922 if (modem_tx != dlci->modem_tx) { 2923 dlci->modem_tx = modem_tx; 2924 gsmtty_modem_update(dlci, 0); 2925 } 2926 } 2927 2928 static const struct tty_port_operations gsm_port_ops = { 2929 .carrier_raised = gsm_carrier_raised, 2930 .dtr_rts = gsm_dtr_rts, 2931 .destruct = gsm_dlci_free, 2932 }; 2933 2934 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2935 { 2936 struct gsm_mux *gsm; 2937 struct gsm_dlci *dlci; 2938 unsigned int line = tty->index; 2939 unsigned int mux = mux_line_to_num(line); 2940 bool alloc = false; 2941 int ret; 2942 2943 line = line & 0x3F; 2944 2945 if (mux >= MAX_MUX) 2946 return -ENXIO; 2947 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2948 if (gsm_mux[mux] == NULL) 2949 return -EUNATCH; 2950 if (line == 0 || line > 61) /* 62/63 reserved */ 2951 return -ECHRNG; 2952 gsm = gsm_mux[mux]; 2953 if (gsm->dead) 2954 return -EL2HLT; 2955 /* If DLCI 0 is not yet fully open return an error. 2956 This is ok from a locking 2957 perspective as we don't have to worry about this 2958 if DLCI0 is lost */ 2959 mutex_lock(&gsm->mutex); 2960 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 2961 mutex_unlock(&gsm->mutex); 2962 return -EL2NSYNC; 2963 } 2964 dlci = gsm->dlci[line]; 2965 if (dlci == NULL) { 2966 alloc = true; 2967 dlci = gsm_dlci_alloc(gsm, line); 2968 } 2969 if (dlci == NULL) { 2970 mutex_unlock(&gsm->mutex); 2971 return -ENOMEM; 2972 } 2973 ret = tty_port_install(&dlci->port, driver, tty); 2974 if (ret) { 2975 if (alloc) 2976 dlci_put(dlci); 2977 mutex_unlock(&gsm->mutex); 2978 return ret; 2979 } 2980 2981 dlci_get(dlci); 2982 dlci_get(gsm->dlci[0]); 2983 mux_get(gsm); 2984 tty->driver_data = dlci; 2985 mutex_unlock(&gsm->mutex); 2986 2987 return 0; 2988 } 2989 2990 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2991 { 2992 struct gsm_dlci *dlci = tty->driver_data; 2993 struct tty_port *port = &dlci->port; 2994 2995 port->count++; 2996 tty_port_tty_set(port, tty); 2997 2998 dlci->modem_rx = 0; 2999 /* We could in theory open and close before we wait - eg if we get 3000 a DM straight back. This is ok as that will have caused a hangup */ 3001 tty_port_set_initialized(port, 1); 3002 /* Start sending off SABM messages */ 3003 gsm_dlci_begin_open(dlci); 3004 /* And wait for virtual carrier */ 3005 return tty_port_block_til_ready(port, tty, filp); 3006 } 3007 3008 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 3009 { 3010 struct gsm_dlci *dlci = tty->driver_data; 3011 3012 if (dlci == NULL) 3013 return; 3014 if (dlci->state == DLCI_CLOSED) 3015 return; 3016 mutex_lock(&dlci->mutex); 3017 gsm_destroy_network(dlci); 3018 mutex_unlock(&dlci->mutex); 3019 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 3020 return; 3021 gsm_dlci_begin_close(dlci); 3022 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 3023 tty_port_lower_dtr_rts(&dlci->port); 3024 tty_port_close_end(&dlci->port, tty); 3025 tty_port_tty_set(&dlci->port, NULL); 3026 return; 3027 } 3028 3029 static void gsmtty_hangup(struct tty_struct *tty) 3030 { 3031 struct gsm_dlci *dlci = tty->driver_data; 3032 if (dlci->state == DLCI_CLOSED) 3033 return; 3034 tty_port_hangup(&dlci->port); 3035 gsm_dlci_begin_close(dlci); 3036 } 3037 3038 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 3039 int len) 3040 { 3041 int sent; 3042 struct gsm_dlci *dlci = tty->driver_data; 3043 if (dlci->state == DLCI_CLOSED) 3044 return -EINVAL; 3045 /* Stuff the bytes into the fifo queue */ 3046 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock); 3047 /* Need to kick the channel */ 3048 gsm_dlci_data_kick(dlci); 3049 return sent; 3050 } 3051 3052 static int gsmtty_write_room(struct tty_struct *tty) 3053 { 3054 struct gsm_dlci *dlci = tty->driver_data; 3055 if (dlci->state == DLCI_CLOSED) 3056 return -EINVAL; 3057 return TX_SIZE - kfifo_len(&dlci->fifo); 3058 } 3059 3060 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3061 { 3062 struct gsm_dlci *dlci = tty->driver_data; 3063 if (dlci->state == DLCI_CLOSED) 3064 return -EINVAL; 3065 return kfifo_len(&dlci->fifo); 3066 } 3067 3068 static void gsmtty_flush_buffer(struct tty_struct *tty) 3069 { 3070 struct gsm_dlci *dlci = tty->driver_data; 3071 if (dlci->state == DLCI_CLOSED) 3072 return; 3073 /* Caution needed: If we implement reliable transport classes 3074 then the data being transmitted can't simply be junked once 3075 it has first hit the stack. Until then we can just blow it 3076 away */ 3077 kfifo_reset(&dlci->fifo); 3078 /* Need to unhook this DLCI from the transmit queue logic */ 3079 } 3080 3081 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3082 { 3083 /* The FIFO handles the queue so the kernel will do the right 3084 thing waiting on chars_in_buffer before calling us. No work 3085 to do here */ 3086 } 3087 3088 static int gsmtty_tiocmget(struct tty_struct *tty) 3089 { 3090 struct gsm_dlci *dlci = tty->driver_data; 3091 if (dlci->state == DLCI_CLOSED) 3092 return -EINVAL; 3093 return dlci->modem_rx; 3094 } 3095 3096 static int gsmtty_tiocmset(struct tty_struct *tty, 3097 unsigned int set, unsigned int clear) 3098 { 3099 struct gsm_dlci *dlci = tty->driver_data; 3100 unsigned int modem_tx = dlci->modem_tx; 3101 3102 if (dlci->state == DLCI_CLOSED) 3103 return -EINVAL; 3104 modem_tx &= ~clear; 3105 modem_tx |= set; 3106 3107 if (modem_tx != dlci->modem_tx) { 3108 dlci->modem_tx = modem_tx; 3109 return gsmtty_modem_update(dlci, 0); 3110 } 3111 return 0; 3112 } 3113 3114 3115 static int gsmtty_ioctl(struct tty_struct *tty, 3116 unsigned int cmd, unsigned long arg) 3117 { 3118 struct gsm_dlci *dlci = tty->driver_data; 3119 struct gsm_netconfig nc; 3120 int index; 3121 3122 if (dlci->state == DLCI_CLOSED) 3123 return -EINVAL; 3124 switch (cmd) { 3125 case GSMIOC_ENABLE_NET: 3126 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3127 return -EFAULT; 3128 nc.if_name[IFNAMSIZ-1] = '\0'; 3129 /* return net interface index or error code */ 3130 mutex_lock(&dlci->mutex); 3131 index = gsm_create_network(dlci, &nc); 3132 mutex_unlock(&dlci->mutex); 3133 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3134 return -EFAULT; 3135 return index; 3136 case GSMIOC_DISABLE_NET: 3137 if (!capable(CAP_NET_ADMIN)) 3138 return -EPERM; 3139 mutex_lock(&dlci->mutex); 3140 gsm_destroy_network(dlci); 3141 mutex_unlock(&dlci->mutex); 3142 return 0; 3143 default: 3144 return -ENOIOCTLCMD; 3145 } 3146 } 3147 3148 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3149 { 3150 struct gsm_dlci *dlci = tty->driver_data; 3151 if (dlci->state == DLCI_CLOSED) 3152 return; 3153 /* For the moment its fixed. In actual fact the speed information 3154 for the virtual channel can be propogated in both directions by 3155 the RPN control message. This however rapidly gets nasty as we 3156 then have to remap modem signals each way according to whether 3157 our virtual cable is null modem etc .. */ 3158 tty_termios_copy_hw(&tty->termios, old); 3159 } 3160 3161 static void gsmtty_throttle(struct tty_struct *tty) 3162 { 3163 struct gsm_dlci *dlci = tty->driver_data; 3164 if (dlci->state == DLCI_CLOSED) 3165 return; 3166 if (C_CRTSCTS(tty)) 3167 dlci->modem_tx &= ~TIOCM_DTR; 3168 dlci->throttled = true; 3169 /* Send an MSC with DTR cleared */ 3170 gsmtty_modem_update(dlci, 0); 3171 } 3172 3173 static void gsmtty_unthrottle(struct tty_struct *tty) 3174 { 3175 struct gsm_dlci *dlci = tty->driver_data; 3176 if (dlci->state == DLCI_CLOSED) 3177 return; 3178 if (C_CRTSCTS(tty)) 3179 dlci->modem_tx |= TIOCM_DTR; 3180 dlci->throttled = false; 3181 /* Send an MSC with DTR set */ 3182 gsmtty_modem_update(dlci, 0); 3183 } 3184 3185 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3186 { 3187 struct gsm_dlci *dlci = tty->driver_data; 3188 int encode = 0; /* Off */ 3189 if (dlci->state == DLCI_CLOSED) 3190 return -EINVAL; 3191 3192 if (state == -1) /* "On indefinitely" - we can't encode this 3193 properly */ 3194 encode = 0x0F; 3195 else if (state > 0) { 3196 encode = state / 200; /* mS to encoding */ 3197 if (encode > 0x0F) 3198 encode = 0x0F; /* Best effort */ 3199 } 3200 return gsmtty_modem_update(dlci, encode); 3201 } 3202 3203 static void gsmtty_cleanup(struct tty_struct *tty) 3204 { 3205 struct gsm_dlci *dlci = tty->driver_data; 3206 struct gsm_mux *gsm = dlci->gsm; 3207 3208 dlci_put(dlci); 3209 dlci_put(gsm->dlci[0]); 3210 mux_put(gsm); 3211 } 3212 3213 /* Virtual ttys for the demux */ 3214 static const struct tty_operations gsmtty_ops = { 3215 .install = gsmtty_install, 3216 .open = gsmtty_open, 3217 .close = gsmtty_close, 3218 .write = gsmtty_write, 3219 .write_room = gsmtty_write_room, 3220 .chars_in_buffer = gsmtty_chars_in_buffer, 3221 .flush_buffer = gsmtty_flush_buffer, 3222 .ioctl = gsmtty_ioctl, 3223 .throttle = gsmtty_throttle, 3224 .unthrottle = gsmtty_unthrottle, 3225 .set_termios = gsmtty_set_termios, 3226 .hangup = gsmtty_hangup, 3227 .wait_until_sent = gsmtty_wait_until_sent, 3228 .tiocmget = gsmtty_tiocmget, 3229 .tiocmset = gsmtty_tiocmset, 3230 .break_ctl = gsmtty_break_ctl, 3231 .cleanup = gsmtty_cleanup, 3232 }; 3233 3234 3235 3236 static int __init gsm_init(void) 3237 { 3238 /* Fill in our line protocol discipline, and register it */ 3239 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3240 if (status != 0) { 3241 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3242 status); 3243 return status; 3244 } 3245 3246 gsm_tty_driver = alloc_tty_driver(256); 3247 if (!gsm_tty_driver) { 3248 tty_unregister_ldisc(N_GSM0710); 3249 pr_err("gsm_init: tty allocation failed.\n"); 3250 return -EINVAL; 3251 } 3252 gsm_tty_driver->driver_name = "gsmtty"; 3253 gsm_tty_driver->name = "gsmtty"; 3254 gsm_tty_driver->major = 0; /* Dynamic */ 3255 gsm_tty_driver->minor_start = 0; 3256 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3257 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3258 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3259 | TTY_DRIVER_HARDWARE_BREAK; 3260 gsm_tty_driver->init_termios = tty_std_termios; 3261 /* Fixme */ 3262 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3263 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3264 3265 spin_lock_init(&gsm_mux_lock); 3266 3267 if (tty_register_driver(gsm_tty_driver)) { 3268 put_tty_driver(gsm_tty_driver); 3269 tty_unregister_ldisc(N_GSM0710); 3270 pr_err("gsm_init: tty registration failed.\n"); 3271 return -EBUSY; 3272 } 3273 pr_debug("gsm_init: loaded as %d,%d.\n", 3274 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3275 return 0; 3276 } 3277 3278 static void __exit gsm_exit(void) 3279 { 3280 int status = tty_unregister_ldisc(N_GSM0710); 3281 if (status != 0) 3282 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3283 status); 3284 tty_unregister_driver(gsm_tty_driver); 3285 put_tty_driver(gsm_tty_driver); 3286 } 3287 3288 module_init(gsm_init); 3289 module_exit(gsm_exit); 3290 3291 3292 MODULE_LICENSE("GPL"); 3293 MODULE_ALIAS_LDISC(N_GSM0710); 3294